"The cause of the disease remains a mystery. No fungous or other parasite can be detected in the earliest stages. The appearance of the trees leads us to infer that the trouble is internal, due to some derangement of the nutritive or assimilative functions of the plant, but we are unable to correlate this with any corresponding external conditions. That is to say, that so many cases have been observed on fertile soil, when cultivation, drainage and plant food had all been provided, that it is impossible to conclude that the disease could be due to starvation or to the lack of any single element in the soil, nor can it be due to over-feeding, since it occurs in light soils and in neglected orchards.

"It seems probable that it will be classed by the plant pathologist with peach rosette, peach yellows, and related diseases, the causes of which still remain unknown after years of investigation. The indications are that it is contagious, though a complete demonstration of this point remains to be made; at any rate, it must be regarded with concern until more knowledge is available."

The best recommendation that can be made in regard to pecans affected by this disease is to dig them up and burn them.

Bordeaux Mixture.
Copper sulphate,5 pounds.
Lime (unslacked),5 pounds.
Water,50 gallons.

Dissolve the copper sulphate in two gallons of water, place it in barrel No. 1 and add water to make twenty-five gallons. Slack the lime, reduce it to a very thin paste, place it in barrel No. 2 and add water to make twenty-five gallons. To mix the solutions of lime and copper sulphate, dip a bucketful from each barrel, and pour together into the barrel of the spray pump. The two mixtures should flow together as they are poured into the barrel. This is one of the secrets of making a first-class mixture. The best arrangement is to have the barrels, Nos. 1 and 2, elevated, and use a piece of rubber hose to run the liquids into the pump barrel.

If a large amount of spraying is to be done, a somewhat different policy should be pursued. Too much time would be taken up in preparing the ingredients in small quantities. Instead, large amounts of copper sulphate should be dissolved and large quantities of lime slacked beforehand. This may be done as follows:

In a fifty-gallon barrel place about forty gallons of water. Put one hundred pounds of copper sulphate in a sack and suspend it in the water. As soon as dissolved, fill up to the fifty-gallon mark. When well stirred, each gallon will contain two pounds of copper sulphate. Each time some of the solution is dipped out, the height of the remaining portion should be marked on the inside of the barrel. Before taking more of the solution out of the barrel, any amount of water lost by evaporation should be made good by filling up to the mark last made.

As soon as procured the lime should be slacked, placed in a barrel and kept covered with an inch or two of water. In this way it can be kept indefinitely.

To prepare Bordeaux mixture from these stock solutions, dip out two and a half gallons of the copper sulphate solution, place it in barrel No. 1 and dilute to twenty-five gallons. From the slacked lime take fifteen pounds, or thereabouts, to allow for the water it contains, reduce to a thin paste, place it in barrel No. 2 and add water to make twenty-five gallons. Pour the contents of barrels Nos. 1 and 2 together, as already directed.

Tests: If free copper be present, severe injury may be done to the foliage or other tender parts of the plants. Sufficient lime should be added to neutralize it.